1. Technical Field
This invention relates generally to joints for linking relatively movable vehicle steering components to one another, and more particularly to tie rod ends.
2. Related Art
Vehicle suspension systems and steering systems typically include joints, such as tie rod end ball-type joints for operable attachment of a tie rod end to a steering knuckle and a ball joint for coupling the steering knuckle to a steering yoke. In addition, other applications, such as carnival rides or any other application having relatively movable joints, typically have ball joints to facilitate the relative movement between linked components. Upon assembly of the tie rod end ball joints, it is generally desirable to build in frictional resistance to joint movement that is within a predetermined torque tolerance. If the frictional resistance or torque is too high or too low, the ball joint may exhibit a reduce life in use, and further, can result in a perceived “feel” that indicates the part as being undesirable. For example, if the tie rod end exhibits frictional resistance that is in excess of the desired tolerance limit, the vehicle operator or mechanic may “feel” the high torque required to move the tie rod end, and thus, believe the tie rod end to be less than desirable. However, a tradeoff exists in that if the tie rod end is assembled with an initially desired torque resulting in a “feel” of perceived quality, the frictional resistance of the tie rod end decreases from the initially set limit, and thus, eventually results in a perceived loose feel, which can also result in replacement or servicing of the tie rod end. Accordingly, a tradeoff exists between providing a tie rod end with an initially high degree of frictional resistance and providing a tie rod end with an initially low degree of frictional resistance.
Efforts have been made to coat ball joints to provide an initially reduced, desired level of frictional resistance, while at the same time providing the ball joint with a long and useful life. However, all known efforts of coating a ball joint have resulted in the frictional resistance of the ball joint either remaining initially too high and/or with the coating being prematurely being scraped off the coated surface.